1. Field of the Invention
This invention relates to the improvement of the document feeding belt for the automatic document feeding apparatus to be attached to the copier such as electrophotographic copying machine.
2. Description of the Prior Art
The automatic document feeding apparatus used in an electrophotographic copying machine (it is referred as copier, sometimes.) is so composed that the automatic document feeding apparatus 1 is positioned onto the surface of the original stand or copy board 3 of the copier 2 as is shown by FIG. 1 (the construction of the copier is not shown, since it is well known in this field.) and the originals (not shown) stacked on the original preparing rest 4 are led toward a feeding belt 7 which is formed with endless and suspended between a driving roller 8 and a driven roller 9 by means of rotation of the feeding roller 5 and a pair of idle rollers 6 which is positioned between the feeding roller 5 and the feeding belt 7. And it is so composed that the feeding belt 7 runs on the surface of the copy board of the copier by means of the driving roller 8 and the driven roller 9 and by means of such running of the belt in a loop, in accordance with the copying operation, and then an original is fed to the predetermined position the copy board 3, at that time the feeding belt 7 is stopped by stopping signal and an stopper (no reference symbol) is out on the copy board so as to engage with a front edge of the original, as is well known. After the completion of the exposure process, the original is delivered to an original receiver 11 through an outlet 10 provided on the top surface of the apparatus by the resumption of the running of the belt.
When the copying operation is carried out by use of such an apparatus, if the size of the original to be copied is smaller than that of the original which has maximum size possible for copy, the image or shadow of the feeding belt 7 positioning outside of the original is also projected onto the surface of photoconductive member (not shown) such as Se, Zno, Cds and so on, simultaneously. Generally, in case of the feeding belt of such kind, plural belts each of which is comparatively narrow in width are juxtaposed with respective spaces. Therefore, from the view point of image quality, it is not desirable that the image of the plural narrow belts is copied in the form that it follows the image of the original. In case of the copier mentioned above, however, if the surface of the narrow belts has white colour and such image of narrow belts is projected onto the surface of the photoconductive member by the white luminessence lamp through a proper optical members (not shown) including an objective lens and a reflecting mirror, no traces thereof will be shown on the member after developing process has been done, because an electric charge on the surface of the photoconductive member where the image of the belts is positioned is totally eliminated. Therefore, in order to prevent the aforesaid drawback, it is satisfactory that all of the narrow belts are made up of the material that is hard to be stained and has high whiteness. However, the restriction that the belt itself must have a high coefficient of friction is essentially imposed, because in case of the automatic document feeding apparatus of such kind, the feeding belt itself is driven by the frictional force of the driving roller 8 and there is a tendency that a possible slip between the driving roller 8 and the belt 7 would directly have an influence on the document feeding performance. In this case, it is convenient if the material of belt that is high both in its whiteness and its coefficient of friction is available, but in case the proper material is not available, the aforesaid problem would be a serious drawback.
This invention has been devised in order to prevent such drawback.